You basically need to rebuild it without the face in question. There is no other way. Example from the archives below ..
http://www.blitzbasic.com/codearcs/codearcs.php?code=1080
http://www.blitzbasic.com/codearcs/codearcs.php?code=1080
The forum is locked. These are the original blitzbasic.com forums, kept so they can still be read. No new topics, replies or edits can be made here. To join in, head over to the Blitz3D+ forums.